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KR-102961620-B1 - light Olefin High Rate Conversion Method and Conversion Device of Waste Plastic

KR102961620B1KR 102961620 B1KR102961620 B1KR 102961620B1KR-102961620-B1

Abstract

The present disclosure relates to a method for manufacturing light olefins, and in detail, can increase the manufacturing yield of light olefins and minimize the generation of carbon dioxide. The method for manufacturing light olefins according to the present disclosure comprises: S1) a step of producing pyrolysis oil and pyrolysis gas by pyrolyzing waste plastics; S2) a step of separating the pyrolysis oil and pyrolysis gas; S3) a step of purifying the separated pyrolysis gas to produce a first gas from which impurities have been removed; S4) a step of producing a second gas by steam reforming the first gas; S5) a step of producing a first synthesis gas from the second gas; S6) a step of producing a second synthesis gas by converting carbon monoxide in the synthesis gas into hydrogen and carbon dioxide through a water-gas shift reaction; and a step of producing a first mixture containing methanol by converting the second synthesis gas into methanol through a hydrogenation reaction. and S8) a step of preparing a second mixture containing a light olefin through an olefin conversion reaction of the methanol contained in the first mixture, and recovering the light olefin from the second mixture;

Inventors

  • 전희중
  • 김옥윤
  • 윤동민

Assignees

  • 에스케이이노베이션 주식회사

Dates

Publication Date
20260511
Application Date
20231218

Claims (20)

  1. S1) A step of producing pyrolysis oil and pyrolysis gas by pyrolyzing waste plastic; S2) A step of separating the above pyrolysis oil and pyrolysis gas; S3) A step of purifying the separated pyrolysis gas to produce a first gas from which impurities have been removed; S4) A step of producing a second gas by steam reforming the first gas; S5) A step of producing a first synthesis gas from the second gas; S6) A step of producing a second synthesis gas by converting carbon monoxide in the first synthesis gas into hydrogen and carbon dioxide through a water-gas shift reaction; S7) A step of converting the second synthesis gas into methanol through a methanol conversion reaction; and S8) A step of converting the methanol into a light olefin through an olefin conversion reaction; comprising a method for producing a light olefin.
  2. In paragraph 1, The above step S3) is, A step of producing a first gas by removing impurities from the separated pyrolysis gas; and A method for producing a light olefin, comprising the step of separating the olefin from the first gas.
  3. In paragraph 2, A method for producing a light olefin, wherein the above olefin is mixed with the light olefin of step S8) and recovered.
  4. In paragraph 2, A method for producing a light olefin in which the above-mentioned impurities include one or more selected from the group consisting of tar, sulfur, nitrogen, and chlorine.
  5. In paragraph 1, A method for producing light olefins, wherein in step S4) above, the second gas comprises hydrogen, carbon monoxide, and carbon dioxide.
  6. In paragraph 1, The above step S5) is, A step of separating the second gas into a first stream containing carbon dioxide and a second stream containing hydrogen and carbon monoxide; A step of converting the first stream into a third stream containing carbon monoxide through a reverse Boudah reaction; and A method for producing a light olefin, comprising the step of mixing the third stream and the second stream to produce a first synthesis gas.
  7. In paragraph 1, A method for producing light olefins, wherein the above pyrolysis oil comprises one or more fractions selected from the group consisting of aromatic fractions, naphtha, and heavy fractions.
  8. In paragraph 1, A method for producing a light olefin, wherein the pyrolysis temperature of step S1) above is 400 to 600 ℃.
  9. In paragraph 1, A method for producing a light olefin, wherein in step S4) above, the steam reforming reaction is carried out under a catalyst, and the catalyst is a composite catalyst in which a metal hydride is supported on a support.
  10. In Paragraph 9, A method for producing a light olefin, wherein the above-mentioned hydride metal is one or more selected from the group consisting of nickel, vanadium, iron, platinum, palladium, or ruthenium.
  11. In paragraph 6, A method for producing light olefins, wherein the above reverse Boudouard reaction is carried out at a temperature of 800 to 1000℃ and a pressure of 50 to 200KPa.
  12. In paragraph 1, A method for producing a light olefin, wherein the second synthesis gas comprises hydrogen and carbon monoxide, and the molar ratio of hydrogen to carbon monoxide is 1.9 to 2.1:1.
  13. In paragraph 1, A method for producing a light olefin, wherein step S7) is performed at a temperature of 400 to 600°C and a pressure of 1 to 10 bar.
  14. In paragraph 1, A method for producing a light olefin, wherein the methanol conversion product of step S7) contains at least 10 wt% methanol based on the total weight of the product.
  15. In paragraph 1, A method for producing a light olefin, wherein step S8) is performed under a zeolite-based catalyst or an AlPO4- based molecular sieve catalyst.
  16. In paragraph 15, A method for producing light olefins, wherein the zeolite-based catalyst or AlPO4- based molecular sieve catalyst is ZSM-5, SAPO-34, or a combination thereof.
  17. A first reactor in which organic waste is pyrolyzed to produce pyrolysis oil and pyrolysis gas; A purification unit that receives the above pyrolysis gas and generates purified pyrolysis gas; A second reactor that receives the above-mentioned purified pyrolysis gas and generates a second gas through a steam reforming reaction; A first synthesis gas generating unit for producing a first synthesis gas from the above second gas; A second synthesis gas generation unit that produces a second synthesis gas by converting carbon monoxide in the first synthesis gas into hydrogen and carbon dioxide through a water-gas shift reaction; and A third reactor that produces methanol through a methanol conversion reaction of the second synthesis gas; and A light olefin manufacturing apparatus comprising: a fourth reactor that produces light olefins through an olefin conversion reaction of the above methanol.
  18. In Paragraph 17, A light olefin manufacturing apparatus comprising: an impurity removal unit for removing impurities; and an olefin separation unit for separating and recovering olefins.
  19. In Paragraph 17, The first synthesis gas generation unit is, A light olefin manufacturing apparatus comprising: an amine scrubber that separates carbon dioxide by receiving the second gas; and a reverse Boudah reactor that performs a reverse Boudah reaction by receiving the carbon dioxide separated from the amine scrubber.
  20. In Paragraph 17, A light olefin manufacturing apparatus comprising the first to fourth reactors, wherein the reactors include a fluidized bed reactor or a fixed bed reactor.

Description

Light Olefin High Rate Conversion Method and Conversion Device of Waste Plastic The present disclosure relates to a method and apparatus for manufacturing light olefins using waste plastics as raw materials, and more specifically, to a method and apparatus for manufacturing light olefins capable of increasing the production yield of light olefins from waste plastics and minimizing the generation of carbon dioxide. Waste plastic is manufactured using petroleum as a raw material; it has a low recyclability and is mostly disposed of as waste. Since these wastes take a long time to decompose in nature, they contaminate the soil and cause serious environmental pollution. One method for recycling waste plastic is to convert it into usable oil through pyrolysis. Since waste plastics are a mixture of hydrocarbon fractions with varying boiling points and molecular weight distributions, the process of producing waste plastic pyrolysis oil generates not only liquid pyrolysis oil but also gaseous pyrolysis gas simultaneously, with the gas being produced in quantities comparable to the liquid oil. While the liquid pyrolysis oil was utilized as fuel and a raw material for various petrochemical industries after undergoing separation and purification processes, the pyrolysis gas was either reused as pyrolysis fuel or released into the atmosphere after passing through heat exchangers. However, these exhaust gases contain large amounts of carbon dioxide, raising concerns regarding the need to meet greenhouse gas emission standards, as well as environmental pollution issues due to other impurities contained within the gases. Meanwhile, light olefins refer to ethylene, propylene, and butene obtained from the cracking of naphtha, serving as essential basic raw materials for the petrochemical industry used in the manufacture of various chemical products such as synthetic resins, synthetic rubber, and alcohols. To date, most ethylene or propylene has been produced through pyrolysis in a steam atmosphere at temperatures exceeding 800°C under catalyst-free conditions, targeting hydrocarbon fractions primarily composed of paraffinic compounds, such as natural gas, naphtha fractions, and gas oil. However, due to the recent sharp rise in crude oil prices, the cost of raw materials for light olefins has become very high. Furthermore, the production process releases massive amounts of carbon dioxide, a cause of global warming, making it necessary to develop processes for producing light olefins from resources other than crude oil in order to reduce these emissions. To solve the aforementioned problems, there have been attempts to produce such light olefins from waste plastic pyrolysis oil. However, waste plastic pyrolysis oil contains an excessive amount of impurities such as chlorine, nitrogen, or metals compared to the fuel components, which significantly reduces reaction activity and conversion efficiency. Furthermore, it is difficult to produce high-quality light olefins, making it difficult to commercially and economically apply. Pyrolysis gas generated during the pyrolysis of waste plastics is attracting attention as a raw material for light olefins because it contains less impurity content, such as chlorine and nitrogen, than pyrolysis oil, while containing a large amount of hydrocarbons such as methane and olefins. However, the process of producing light olefins from pyrolysis gas has low productivity, making it difficult to utilize and commercialize. Accordingly, there is a need for research on methods and devices capable of converting light olefins from waste plastics with high yield. FIG. 1 is a schematic diagram illustrating a method for manufacturing a light olefin according to the present disclosure. FIG. 2 is a schematic diagram showing a method for manufacturing a light olefin according to one embodiment of the present disclosure. FIG. 3 is a schematic diagram showing a light olefin manufacturing apparatus according to the present disclosure. FIG. 4 is a schematic diagram showing a light olefin manufacturing apparatus according to one embodiment of the present disclosure. FIG. 5 is a schematic diagram showing an olefin separation unit according to one embodiment of the present disclosure. Unless otherwise specifically indicated, the singular form of a term used in this specification may be interpreted to include the plural form. The numerical ranges used herein include lower and upper limits, all values within the range, all values limited thereto, and all possible combinations of upper and lower limits of the numerical ranges limited in different forms. Unless otherwise specifically defined in this specification, values outside the numerical range that may occur due to experimental error or rounding are also included within the defined numerical ranges. As used in this specification, "comprising" is an open description equivalent to expressions such as "comprising," "containing," "having," and "characteristics," and doe